ABSTRACT
Polycyclic aromatic hydrocarbons (PAHs) are persistent contaminants in the environment. Several of them have carcinogenic properties. There is considerable interest in their sensitive low-cost detection and monitoring. We present a simple paper-based microfluidic sensor for the rapid detection of PAHs. Craft punch patterning generated multiple detection zones inhabited by fluorescent poly(arylene ethynylene)s (PAEs). Changes in fluorescence image and/or intensity of the sensor array were recorded using a smartphone camera. The RGB color values of the photographed images were extracted through ImageJ software. 10 different PAHs were correctly identified using Principal Component Analysis and discrimination analysis (PCA-DA). 100% classification accuracy was achieved for model training, whereas validating the PCA-DA model by cross-validation resulted in 93% classification accuracy for 5.0 mg L-1 analyte.
Subject(s)
Polycyclic Aromatic Hydrocarbons , Carcinogens/analysis , Environmental Monitoring , Microfluidics , Polycyclic Aromatic Hydrocarbons/analysis , Principal Component AnalysisABSTRACT
A cross-reactive optical sensor array based on poly(p-phenyleneethynylene)s (PPEs) determines Edman degraded amino acids. We report a sensor array composed of three anionic PPEs P1-P3, and their electrostatic complexes with metal ions (Fe2+ , Cu2+ , Co2+ ). We recorded distinct fluorescence intensity response patterns as "fingerprints" of this chemical tongue toward standard phenylthiohydantoin (PTH) amino acids-degradation products of the Edman process. These "fingerprints" were converted into canonical scores by linear discrimination analysis (LDA), which differentiates all of the PTH-amino acids. This array discriminates PTH-amino acid residues degraded from an oligopeptide through Edman sequencing. This approach is complementary to chromatography approaches which rely on mass spectrometry; our array offers the advantage of simplicity.
ABSTRACT
Four tetraphenylethylene (TPE)-based aryleneethynylene polymers with amino or nitro groups are reported. They display strong aggregation-induced emission (AIE). The functional groups trigger acidochromic changes in the emission behavior of these polymers. Amino-substituted P1-P3 exhibit pH response through protonation of the amino groups. The position of the amino groups (on TPE or the side chains) influences the fluorescence intensity or emission wavelength as a response to different pH values. Nitro-P4 is solvatochromic due to its donor-acceptor structure. AIE, intramolecular charge transfer, and Förster resonance energy transfer define the fluorescence-based performance of the polymers. The amino-functionalized TPE polymers show excellent nitroarene-sensing performance. P4 is less effective than the amino polymers. A sensor array based on P1-P3 identifies 12 different nitroarenes in water.
Subject(s)
Fluorescent Dyes/chemistry , Nitro Compounds/analysis , Polymers/chemistry , Stilbenes/chemistry , Fluorescence Resonance Energy Transfer , Fluorescent Dyes/chemical synthesis , Hydrogen-Ion Concentration , Molecular Structure , Polymers/chemical synthesis , Solvents/chemistryABSTRACT
Fluorescent, water-soluble poly(p-aryleneethynylene)s (PAE) were immobilized on commercially available nylon membranes by using a slot plotter, creating fluorescent, barcode-like sensor strips. Digital imaging by using a standard digital camera, before and after immersion of the strips in buffers of different pH, displays a unique color for each pH value. Statistical evaluation, multivariate analysis of variance (MANOVA) and principal component analysis (PCA), of the acquired data revealed that the immobilized PAEs are superior to the identical fluorophores when dissolved. The pH sensor array discriminates 20â different brands of commercial-cola soft drinks through differences in pH and colorant-PAE interactions.
ABSTRACT
The synthesis and quenching behavior of a series of water-soluble, carboxylate-carrying phenyleneethynylene oligomers-monomer to tetramer-and their polymers are reported; their quenching behavior with different test analytes (paraquat, lead salts, mercury salts, picric acid, methylpyridinium iodide) in water were investigated, and the results were compared to that of the conjugated polymer. Significant but analyte-dependent enhancement effects were found. For monovalent quenchers, only the molecular wire effect applies, but for divalent quenchers multivalency effects are also important.
ABSTRACT
We report a cross-reactive sensor array, combining a two-component probe system based upon three viologen substituted boronic acids and a poly(aryleneethynylene) (PAE) and an additional number of simple PAEs alone. This combined system discriminates 27 different honeys in aqueous solution, according to patterns in fluorescence intensity modulation, using linear discriminant analysis for data processing. The fluorescence turn-on array detects saccharide composition, while the PAEs discriminate trace colored components in the honeys.
Subject(s)
Biosensing Techniques/methods , Boronic Acids/chemistry , Fluorescent Dyes/chemistry , High Fructose Corn Syrup/analysis , Honey/analysis , Polymers/chemistry , Polyynes/chemistry , Viologens/chemistry , Carbohydrates/analysis , Humans , Spectrometry, Fluorescence , Water/chemistryABSTRACT
A hypothesis-free sensor array (optoelectronic tongue) composed of an anionic, a cationic and two neutral poly(para-aryleneethynylene)s (PAE) at pHâ 3, 7 and 13 discriminate more than 30 spirits (including brandy, Branntwein, Cognac, Spirituose, and Weinbrand). Counterfeits (made by mixing of low-quality spirits and caramel colour) and different batches of identical brands of brandies are discriminated. The sensor array works without sample preparation or great instrumental cost, and is superior to conventional methods with respect to sample need (10-20â µL), time and effort. The discrimination stems from differential fluorescence quenching of the PAE-array by the complex mixture of the beverages' colourants, from the oak barrels or added caramel colour. The collected quenching data were analysed by linear discriminant analysis (LDA) and principal component analysis (PCA) to achieve successful discrimination.
ABSTRACT
We report the development of a two-component probe system as fluorescence turn-on assay of simple saccharides. The quenching of an anionic conjugated water-soluble polymer by a cationic quencher has been reported previously. Three different boronic acid functionalized benzyl viologens and three conjugated polymers of the poly(aryleneethynylene) type form nine non-fluorescent complexes. This small library discriminates nine different simple saccharides in aqueous solutions by fluorescence turn-on in a displacement assay. The saccharides can be discriminated and identified with this simple system.
ABSTRACT
A self-assembled nine-element optoelectronic tongue consisting of a positively charged water-soluble poly(para-phenyleneethynylene) and three metal ions (Fe2+ , Co2+ , and Cu2+ ) at three different pH values (7, 10, and 13) discriminates all of the 20â natural amino acids in water. Unknown identification was not ideal. Addition of a highly positively charged green fluorescent protein in the presence of Fe2+ , Co2+ , and Cu2+ increased the unknown identification to above 86 %. Linear discriminant analysis (LDA) orders the responses according to the amino acid type, that is, hydrophobic, polar, anionic, or cationic.
Subject(s)
Amino Acids/analysis , Electronic Nose , Alkynes/chemistry , Amino Acids/chemistry , Cobalt/chemistry , Copper/chemistry , Discriminant Analysis , Ethers/chemistry , Ferrous Compounds/chemistry , Hydrogen-Ion Concentration , Hydrophobic and Hydrophilic Interactions , Principal Component Analysis , Spectrometry, FluorescenceABSTRACT
We describe a simple optoelectronic tongue, consisting of a positively charged, fluorescent poly(para-phenyleneethynylene), P2, that reacts to fruit juices, when employed at three different pH-values (pH 3, 7, 13). This minimal tongue identifies and discriminates 14 different commercially available apple juices, 6 different grape juices and 5 different black currant juices from each other. A similar, negatively charged fluorescent polymer, P1, also achieved discrimination, but the analyte concentration had to be increased by a factor of 50. A mixture of black currant juice and red grape juice is identified as red grape juice, for specific combinations of grape and black currant juices. A mixture of red and green grape juice passes as red grape juice in our sensing system when it contains more than 70% of red grape juice. The data were obtained by fluorescence quenching of the conjugated polymers and processed by linear discriminant analysis of the collected data.
Subject(s)
Alkynes , Electronic Nose , Ethers , Fruit and Vegetable Juices/analysis , Malus , VitisABSTRACT
A negatively charged poly(para-phenyleneethynylene) (PPE) forms electrostatic complexes with four positively charged antimicrobial peptides (AMP). The AMPs partially quench the fluorescence of the PPE and discriminate fourteen different bacteria in water and in human urine by pattern-based fluorescence recognition; the AMP-PPE complexes bind differentially to the components of bacterial surfaces. The bacterial species and strains form clusters according to staining properties (Gram-positive and Gram-negative) or genetic similarity (genus, species, and strain). The identification and data treatment is performed by pattern evaluation with linear discriminant analysis (LDA) of the collected fluorescence intensity data.
Subject(s)
Alkynes/chemistry , Antimicrobial Cationic Peptides/chemistry , Escherichia coli/chemistry , Escherichia coli/isolation & purification , Ethers/chemistry , Micrococcaceae/chemistry , Micrococcaceae/isolation & purification , Urine/microbiology , Discriminant Analysis , Fluorescence , Humans , Static ElectricityABSTRACT
One fluorescent, positively charged poly(para-phenyleneethynylene) (PAE 1) forms electrostatic complexes with five negatively charged pyridine- or benzothiadiazole-containing poly(para-aryleneethynylene)s (PAE 2-PAE 6). The PAE 2-PAE 6 are less fluorescent in water and act as quenchers for PAE 1 in their electrostatic complexes C 1-C 5; the PAE-complexes (2â µm) were exposed to thirteen different carboxylic acids (50â mm) in buffered aqueous solution. The fluorescence responses of the small library of electrostatic PAE-complexes towards the acids was analyzed; discrimination of all of the thirteen acids was achieved. The investigated acids include acetic, butyric, tartaric, maleic, lactic, sorbic, oxalic, aspartic, and citric acids. A random, simple, ad-hoc library of electrostatic polymer complexes, C 1-C 5, therefore discerns the thirteen carboxylic acids in water.
ABSTRACT
We describe poly(aryleneethynylene)s (PAE) as powerful sensor cores. We discuss concepts (super quenching, molecular wire effect, multivalency) that were developed using PAEs and also the relationship that connects side chain structure (polar, polyelectrolyte, etc., number of ionic groups per repeat, position) and optical properties such as quantum yields. In the second part of the review we discuss applications of PAEs in their interaction with sensor targets; metal cations, fluoride and other anions, explosives, proteins and whole cells being the target for PAEs, while cationic PAEs have been used for the transfection of eukaryotic cells with RNA.
ABSTRACT
We present a simple array composed of an anionic and a cationic poly(para-phenyleneethynylene) (PPE), together with an electrostatic complex between the two of them. The individual PPEs and the PPE complex were employed in the sensing of white wines at pHâ 13; the complex was also successfully employed as a sensor element at pHâ 3. The sensing mechanism is fluorescence quenching. Thirteen different wines were differentiated by this chemical tongue, which consists of four elements. The fluorescence quenching is not induced by the major components of the wines. Compounds such as acids, sugars, and alcohols alone do not quench the fluorescence, but rather the colored tannins and other polyphenols contained in wine are the main quenchers. However, the major constituents of wine significantly modulate the quenching of the PPEs by the tannins.
ABSTRACT
Porous conjugated polymers are synthesized by metal-catalyzed coupling reactions. The progress for porous polymers when planar or tetrahedral building blocks are connected by alkyne units into novel materials is highlighted. The most prominent reaction for the buildup of the microporous alkyne-bridged polymers is the Sonogashira reaction, connecting alkynes to aromatic iodides or bromides. The availability of the building blocks and the potency of the Sonogashira reaction allow preparing a large variety of intrinsically porous polymeric materials, in which rigid struts connect multipronged centers. The microporous polymers are used as catalysts and as storage materials for gases and sensors. Postfunctionalization schemes, understanding of structure-property relationships, and the quest for high porosity are pertinent.
Subject(s)
Gases/chemistry , Polymers/chemistry , Alkynes/chemical synthesis , Alkynes/chemistry , Catalysis , Graphite/chemistry , Metals/chemistry , PorosityABSTRACT
Discrimination of nitroarenes with hydrophobic dyes in a polar (H2O) environment is difficult but possible via a lab-on-chip, with polymeric dyes immobilized on paper or nylon membranes. Here arrays of 12 hydrophobic poly(p-phenyleneethynylene)s (PPEs), are assembled into a chemical tongue to detect/discriminate nitroarenes in water. The changes in fluorescence image of the PPEs when interacting with solutions of the nitroarenes were recorded and converted into color difference maps, followed by cluster analysis methods. The variable selection method for both paper and nylon devices selects a handful of PPEs at different pH-values that discriminate nitroaromatics reliably. The paper-based chemical tongue could accurately discriminate all studied nitroarenes whereas the nylon-based devices represented distinguishable optical signature for picric acid and 2,4,6-trinitrotoluene (TNT) with high accuracy.
ABSTRACT
Some viruses are rarely transmitted orally or sexually despite their presence in saliva, breast milk, or semen. We previously identified that extracellular vesicles (EVs) in semen and saliva inhibit Zika virus infection. However, the antiviral spectrum and underlying mechanism remained unclear. Here we applied lipidomics and flow cytometry to show that these EVs expose phosphatidylserine (PS). By blocking PS receptors, targeted by Zika virus in the process of apoptotic mimicry, they interfere with viral attachment and entry. Consequently, physiological concentrations of EVs applied in vitro efficiently inhibited infection by apoptotic mimicry dengue, West Nile, Chikungunya, Ebola and vesicular stomatitis viruses, but not severe acute respiratory syndrome coronavirus 2, human immunodeficiency virus 1, hepatitis C virus and herpesviruses that use other entry receptors. Our results identify the role of PS-rich EVs in body fluids in innate defence against infection via viral apoptotic mimicries, explaining why these viruses are primarily transmitted via PS-EV-deficient blood or blood-ingesting arthropods rather than direct human-to-human contact.
Subject(s)
Body Fluids , Extracellular Vesicles , Viruses , Zika Virus Infection , Zika Virus , Female , Humans , Phosphatidylserines , Virus AttachmentABSTRACT
The first enantioselective allylic hydroxylation to prepare branched allylic alcohols directly is described. Bicarbonate was used as nucleophile in conjunction with new single component Ir-catalysts, which are stable to air and water. Excellent regio- and enantioselectivities have been achieved with a representative set of substrates.
ABSTRACT
We report a polymer-based sensor that rapidly detects cancer based on changes in serum protein levels. Using three ratiometric fluorescence outputs, this simple system identifies early stage and metastatic lung cancer with a high level of accuracy exceeding many biomarker-based assays, making it an attractive strategy for point-of-care testing.
Subject(s)
Biomarkers, Tumor/blood , Blood Proteins/analysis , Fluorescent Dyes/chemistry , Lung Neoplasms/diagnostic imaging , Polymers/chemistry , Animals , Fluorescence , Humans , Lung Neoplasms/blood , Lung Neoplasms/secondary , Mice , Mice, Transgenic , Molecular Structure , Neoplasms, Experimental/blood , Neoplasms, Experimental/diagnostic imaging , Neoplasms, Experimental/secondary , Point-of-Care TestingABSTRACT
Wet-chemical discrimination of amino acids is still a challenge due to their structural similarity. Here, an optimized self-assembled eight-member sensor array is reported. The optimized sensor array stems from the combination of elements of different tongues, containing poly( para-phenyleneethynylene)s (PPE) and a supercharged green fluorescent protein (GFP) variant. The responsivity of the sensor dyes (PPEs and GFP) is enhanced in elements that contain adjuvants, such as metal salts but also cucurbit[7]uril (CB[7]) and acridine orange; a suitable and robust eight element array discriminates all of the 20 natural amino acids in water at 25 mM concentration with 100% accuracy. The results group well to the amino acid type, i.e., hydrophobic, polar, and aromatic ones.